Answer to Question #9698 in Trigonometry for Fred

Question

In a triangle, Angle "A" is known, and the length of the two adjoining sides. How to find the length of the third side?

Answer 1

we can use cosine theorem so (length of the third side)^2= (length of the first
side)^2+(length of the second side)^2-2*(length of the first side)*(length of
the second side)*cos(A)
length of the third side=sqrt[ (length of the first
side)^2+(length of the second side)^2-2*(length of the first side)*(length of
the second side)*cos(A) ]